(19)
(11) EP 0 550 358 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
02.11.1994 Bulletin 1994/44

(43) Date of publication A2:
07.07.1993 Bulletin 1993/27

(21) Application number: 92420481.1

(22) Date of filing: 23.12.1992
(51) International Patent Classification (IPC)5: G06F 9/46, G06F 15/16, G06F 11/00, G06F 11/18
(84) Designated Contracting States:
DE FR GB

(30) Priority: 30.12.1991 US 813752

(71) Applicant: ATEX PUBLISHING SYSTEMS CORPORATION
Bedford, Massachusetts 07130 (US)

(72) Inventors:
  • Vinther, Gordon A., c/o EASTMAN KODAK COMPANY
    Rochester, New York 14650-2201 (US)
  • Brudevold, Finn, c/o EASTMAN KODAK COMPANY
    Rochester, New York 14650-2201 (US)

(74) Representative: Schoppe, Fritz, Dipl.-Ing. 
Patentanwalt, Georg-Kalb-Strasse 9
D-82049 Pullach
D-82049 Pullach (DE)


(56) References cited: : 
   
       


    (54) Fault tolerant multiprocessor cluster


    (57) The present invention is a system that provides a shared, common memory unit for multiple computers accessing the same database in a multiprocessor transaction type computer network. The memory unit acts as a common repository for the multiple computers and which store data and system state. A bus interface is provided for each computer which allows each computer to be located remotely of the common memory unit. The bus interface allows each computer to write into triplicated memories simultaneously. The interface ensures that the data read out of the memory is correct by voting on the memory outputs and passing to the corresponding computer only the correct data. The system is also provided with fault tolerant clock signals for keeping the triplicated memories operating in synchronism. This along with appropriate software make the group of computers immune to any single point of failure.






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